The Rise of Oral Obesity Therapies: Semaglutide and Orforglipron

SWharton et al. N Engl J Med 2025;393:1077-1087. Oral Semaglutide at a Dose of 25 mg in Adults with Overweight or Obesity

Methods: The participants were randomly assigned in a 2:1 ratio to receive oral semaglutide (25 mg) or placebo once daily, plus lifestyle interventions.

Key Findings:

In their discussion, the authors note that the reasons why “patients may prefer oral administration over the subcutaneous route are most often needle aversion and local skin reactions.7,8 In addition, unlike injectable agents, oral agents may not require a refrigerated chain of delivery and could widen the reach of obesity care in many regions of the world where a lack of refrigeration represents a barrier to access.”

In addition, the results were similar to the “STEP 1 (Semaglutide Treatment Effect in People with Obesity) trial of weekly subcutaneous semaglutide at a dose of 2.4 mg (12.4 percentage points more than that with placebo),16

As with prior trials of semaglutide, “treatment was also associated with substantial reductions in cardiometabolic risk factors including BMI, waist circumference, and levels of glycated hemoglobin, fasting plasma glucose, fasting serum insulin, lipids (very-low-density lipoprotein and triglycerides), and C-reactive protein.”

My take: Effective oral therapy is a big advance for management of obesity. The entire field of pharmacology for obesity has seen remarkable advances in the past few years. For me, it is reminiscent of the proliferation of published studies for hepatitis C around 10 years ago.

Related article in same NEJM issue: J Rosenstock et al. N Engl J Med 2025;393:1065-1076. Orforglipron, an Oral Small-Molecule GLP-1 Receptor Agonist, in Early Type 2 Diabetes

In the ACHIEVE-1 Trial: Key Findings (n=559 adults):

The associated editorial by DB Lowe (N Engl J Med 2025;393:1133-1134) notes that Orforglipron is a small molecule that manages to mimic the effects of glucagon-like peptide-1 (GLP-1) at the GLP-1 receptor. “The incretins, like many peptide hormones, are fairly small as proteins go — a few dozen amino acids long. But that makes them gigantic as compared with small-molecule drugs. Their molecular weights are at least 10 times as high as the 300 to 500 mass units that medicinal chemists have traditionally aimed for, and being peptides, they have generally undesirable properties as well. Many have short half-lives in the circulation, which can be a desirable feature for endogenous peptides but is nowhere near what is needed for the administration of a once-daily dose.”

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Weight Loss Efficacy of Cagrilintide and Semaglutide

WTGarvey et al. N Engl J Med 2025;393:635-647. Coadministered Cagrilintide and Semaglutide in Adults with Overweight or Obesity

This  phase 3a, 68-week, multicenter, double-blind, placebo-controlled and active-controlled trial (REDEFINE 1) examined the efficacy of the combination of Cagrilintide and Semaglutide (known as CagriSema).  Patients had a body-mass index (BMI) of 30 or higher or a BMI of 27 or higher with at least one obesity-related complication. The combination druge was delivered as a fixed-dose in a single-dose, single-use pen device. 6.1% of trial participants had BMI <30.


Percentage of patients with at least 5% weight loss
Percentage of patients with at least 20% weight loss
  • “Gastrointestinal adverse events (affecting 79.6% in the cagrilintide–semaglutide group and 39.9% in the placebo group), including nausea, vomiting, diarrhea, constipation, or abdominal pain, were mainly transient and mild-to-moderate in severity.”
  • “Although 57.4% of the participants assigned to cagrilintide–semaglutide were receiving the maximum dose at 68 weeks, 74.7% had received the maximum dose at some point after randomization…doses below the target might be highly effective for some patients and that dose reductions based on the clinical judgment…may be appropriate.”

This same issue also examined the use of this combination in patients with type 2 diabetes (REDEFINE 2). in this study with 1206 patients, “the estimated mean change in body weight from baseline to week 68 was −13.7% in the cagrilintide–semaglutide group and −3.4% in the placebo group.”

The editorial by CM Hales (“Expanding the Treat-to-Target Toolbox for Obesity and Diabetes Care”) notes that “six deaths occurred in the two trials combined, all in the cagrilintide–semaglutide groups, including one suicide in each trial. Previous studies of suicidality with GLP-1 receptor agonist treatment have not supported a causal link,6 but it continues to be of concern.”

My take (from the editorial): “A sustainable treat-to-target approach should extend to lifelong maintenance of health gains after initial weight loss. The intensity and composition of lifestyle interventions in the context of highly effective pharmacologic therapies also need further study. The pharmaceutical pipeline is promising, with potential improvements in safety (such as preservation of lean mass) and more convenience for patients (such as oral administration and monthly dosing). Greater effects on the health of Americans may be achieved not with antiobesity medications producing ever greater magnitudes of weight loss but with expanded access to safe and effective therapies for those who would most benefit.”

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FDA Approves Semaglutide for MASH

Dani Blum, NY Times 8/18/25: A Common Weight Loss Drug Can Treat Severe Liver Disease, F.D.A. Says

An excerpt:

Roughly 15 million people — six percent of adults in the United States — have metabolic dysfunction-associated steatohepatitis, known as MASH. Rates of the disease are rising…

Wegovy, which is a weekly injection, is now approved for adults with MASH and moderate-to-advanced levels of fibrosis, or excessive scar tissue in the liver. The drug is not intended for people with cirrhosis…

Wegovy will be a welcome addition to the options doctors can prescribe — as long as their patients can access them. The drug carries a list price of over $1,300 a month, although most people do not pay that full amount. Many people have lost insurance coverage for weight-loss drugs, as plans struggle to keep up with the costs.

Related review article: G Targher et al. NEJM 2025; 393: 683-698. Metabolic Dysfunction–Associated Steatotic Liver Disease. This review article succinctly covers the epidemiology, manifestations, disease progression and pivotal pharmacologic advances.

Related blog post: Semaglutide’s Efficacy in Phase 3 MASH Trial

Real-World Results of Obesity Pharmacotherapy With Tirzepatide and Semaglutide

Happy July 4th!


L Gasoyan et al. Obesity 2025; DOI: 10.1002/oby.24331. Open Access! Changes in weight and glycemic control following obesity treatment with semaglutide or tirzepatide by discontinuation status

Methods: This retrospective cohort study used electronic health record data from a large health system in Ohio and Florida to identify adults with overweight or obesity without type 2 diabetes who initiated injectable semaglutide or tirzepatide between 2021 and 2023; 6109 received semaglutide, and 1772 received tirzepatide. Classification as high maintenance doses for semaglutide were 1.7, 2.0, or 2.4 mg and for tirzepatide 10.0, 12.5, or 15.0 mg, and all other dosages classified as low. The study grouped patients who discontinued pharmacotherapy into those who discontinued early (within 3 months of the index date) and late (within 3–12 months)

Key findings:

  • 80.8% had low maintenance dosages
  • Mean (SD) percentage weight reduction at 1 year was 8.7% (9.6%)
  • ~50% discontinued medication within 1 year
  • Patients receiving tirzepatide had more weight loss than those receiving semaglutide (see below). Among patients who did not discontinue obesity pharmacotherapy at year 1, the mean (SD) percentage reduction in weight was 10.9% with semaglutide and 15.3% with tirzepatide
  • In those receiving high dose medication, mean (SD) percentage reduction in weight was 14.7% with semaglutide and 18.0% with tirzepatide
  • Patients who continuing therapy had more weight loss than those who discontinued therapy (see below); Mean (SD) percentage weight reduction at 1 year was 3.6% (8.1%) with early discontinuation, 6.8% (9.1%) with late discontinuation, and 11.9% (9.2%) with non-discontinuation (p < 0.001).

DISCONTINUATION OF THERAPY:

Cumulative incidence of obesity pharmacotherapy discontinuation by index medication. s. Discontinuation of obesity pharmacotherapy was defined as a greater than 90-day gap between exhaustion of previous supply and next dispense or between exhaustion of last supply and end of study follow-up

SEMAGLUTIDE VS TIRZEPATIDE:

RESULTS WITH ONGOING TREATMENT VS TREATMENT DISCONTINUATION:

My take: This study showed higher rates of medication discontinuation in a real world setting compared to prior publications. In addition, the majority were receiving lower doses yet still achieving good results. However, increased discontinuation and lower doses likely explain the discrepancy in weight loss in this cohort which was less than in prior studies. It is important that patients taking these medications receive adequate counseling at the start to improve rates of adherence and long-term outcomes, including mitigation of muscle loss and bone loss.

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Head-to-Head: Tirzepatide Outperforms Semaglutide

LA Aronne et al. NEJM 2025; DOI: 10.1056/NEJMoa2416394. Tirzepatide as Compared with Semaglutide for the Treatment of Obesity

Methods: In this phase 3b, open-label, controlled “SURMOUNT-5” trial, adult participants (n=751) with obesity but without type 2 diabetes were randomly assigned in a 1:1 ratio to receive the maximum tolerated dose of tirzepatide (10 mg or 15 mg) or the maximum tolerated dose of semaglutide (1.7 mg or 2.4 mg) subcutaneously once weekly for 72 weeks

Key findings:

Discussion Points:

“With both treatments in our trial, as weight reduction increased, greater improvements occurred in cardiometabolic risk factors, including blood pressure, glycemia, and lipid levels, which is consistent with the findings in previous reports.17 The mean differences between tirzepatide and semaglutide in the cardiometabolic risk factors may be clinically relevant considering that reductions in systolic blood pressure of 2 to 5 mm Hg have been shown to reduce the risk of cardiovascular events.”

” As typically observed with incretin-based therapies, gastrointestinal adverse events were predominantly mild to moderate in severity, occurred mostly during dose escalation, and led to treatment discontinuation more often with semaglutide than with tirzepatide.”

My take (borrowed from the authors):  “Treatment with tirzepatide, a dual GIP and GLP-1 receptor agonist, was superior to treatment with semaglutide, a selective GLP-1 receptor agonist, with respect to reduction in body weight and waist circumference.”

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Key Insights on MASLD from Dr. Marialena Mouzaki

Dr. Marialena Mouzaki recently gave an excellent ground rounds at Children’s Healthcare of Atlanta. My notes below may contain errors in transcription and in omission. Along with my notes, I have included many of her slides (with permission).

Key points:

  • Epidemiology: Metabolic associated steatotic liver disease (MASLD) is very common and increasing in prevalence
  • There is new terminology and new diagnostic thresholds
  • Treatment cornerstone relies on lifestyle changes including diet modifications and exercise. Small weight reductions (10 lbs in adults)/improvement in BMI (z reduction of >0.25) can be beneficial
  • Diet: No specific diet has proven more effective than others (eg. low carb, Mediterranean). Avoiding simple sugars is helpful
  • Exercise: US children do not get enough physical activity (goal 1 hour daily). Exercise has not been studied well for pediatric MASLD but it has been proven to reduce cardiovascular disease and premature death
  • Medications: Medications are not part of routine care for pediatric MASLD in 2025 When they are available, use without lifestyle changes could be detrimental (eg. sarcopenia, worse cardiometabolic profile, nutritional deficiencies)
  • Multiple GLP-1 RA-containing agents appear promising (Semaglutide, tirzepatide, survodutide). Resmetirom is FDA approved for the treatment of MASLD with stage 2-3 fibrosis in adults.
  • Treat comorbidities like diabetes, obstructive sleep apnea (OSA), dyslipidemia and hypertension. Treatment of OSA may help MASLD
  • The leading cause of mortality in adults with MASLD is due to cardiovascular disease

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Pharmacological Management of Pediatric Steatotic Liver Disease

RARA Jaoudeh et al. J Pediatr Gastroenterol Nutr. 2025;80:14–24; Pharmacological management of pediatric metabolic dysfunction-associated steatotic liver disease

Key points:

  • Glucagon-like peptide-1 receptor agonists (GLP-1RAs) have demonstrated efficacy against adult MASLD. “In patients ≥12 years of age with obesity (BMI ≥ 95th percentile), we recommend the use of GLP-1RA—along with dietary and lifestyle modifications—in those who have MASLD or MASH, and 1 additional metabolic comorbidity (hypertension, prediabetes, polycystic ovary syndrome, dyslipidemia, and obstructive sleep apnea) (Figures 1 and 2). Treatment with these agents should only be initiated after other causes of hepatic steatosis are ruled out.”
  • “GLP-1RA are effective in treating pediatric obesity and have shown to decrease liver enzyme levels which is likely indicative of their effect on MASLD.”
  • “It is important to note that phentermine/topiramate combination drug is approved for patients 12 years and older with obesity15 and can be used as a bridge for GLP-1RA therapy in cases where access to GLP-1RA is limited.”
  • GLP-1RA Dosing regimens are provided in Table 1. For example, “Semaglutide for weight loss is initiated at 0.25 mg once weekly subcutaneously and increased every 4 weeks in a stepwise fashion up to a maximum of 2.4 mg once weekly dose. The most common side effects are nausea and/or vomiting and can be worse the first few days a after dose increase. It is acceptable to delay dose escalation or reduce the target dose based on patient tolerance. Medication therapy should be evaluated for effectiveness after 12 weeks on a maximally tolerated dose.” And, “Liraglutide for weight loss is initiated at 0.6 mg daily subcutaneously and increased weekly in 0.6 mg increments up to a maximum 3 mg daily dose.”
  • Adverse effects: “Both liraglutide and semaglutide have been associated with thyroid C-cell tumors in animal studies37 and are contraindicated in patients with a personal or familial history of multiple endocrine neoplasia 2A and 2B and medullary thyroid carcinoma. Patients should be educated on symptoms of thyroid tumors—lump in the neck, difficulty breathing or swallowing, or persistent hoarseness—and treatment should be discontinued if these occur.37 GLP-1RA also increase the risk of pancreatitis and gallbladder disease especially with rapid weight loss.37 Liraglutide is contraindicated in pregnancy due to potential embryo-fetal defects shown in animal studies, and semaglutide should be discontinued if pregnancy occurs.1037

Useful algorithm:

My take: GLP-RAs are likely to be used increasingly in adolescents with MASLD despite issues with insurance/affordability and need for chronic treatment. This is a helpful review.

Related blog posts:

Disclaimer: This blog, gutsandgrowth, assumes no responsibility for any use or operation of any method, product, instruction, concept or idea contained in the material herein or for any injury or damage to persons or property (whether products liability, negligence or otherwise) resulting from such use or operation. These blog posts are for educational purposes only. Specific dosing of medications (along with potential adverse effects) should be confirmed by prescribing physician.  Because of rapid advances in the medical sciences, the gutsandgrowth blog cautions that independent verification should be made of diagnosis and drug dosages. The reader is solely responsible for the conduct of any suggested test or procedure.  This content is not a substitute for medical advice, diagnosis or treatment provided by a qualified healthcare provider. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a condition.

More Data Indicating GLP-1 Efficacy for MASH

GI and Hepatology News, Open Access: Watershed Moment’: Semaglutide Shown to Be Effective in MASH (November 2024): “At 72 weeks, a 2.4-mg once-weekly subcutaneous dose of semaglutide demonstrated superiority, compared with placebo, for the two primary endpoints: Resolution of steatohepatitis with no worsening of fibrosis and improvement in liver fibrosis with no worsening of steatohepatitis.”

“ESSENCE (NCT04822181) is an ongoing multicenter, phase 3 randomized, double-blind, placebo-controlled outcome trial studying semaglutide for the potential treatment of MASH.” Cohort: N=1200, biopsy-defined MASH and fibrosis, stages F2 and F3…”After initiation, the semaglutide dosage was increased every 4 weeks up to 16 weeks when the full dose (2.4 mg) was reached.”

Key findings:

  • 62.9% of those in the semaglutide group and 34.1% of those in the placebo group reached resolution of steatohepatitis with no worsening of fibrosis. 
  • 37% of those in the semaglutide group and 22.5% of those in the placebo group had improvement in liver fibrosis with no worsening of steatohepatitis
  • Weight loss was also significant, with a 10.5% reduction in the semaglutide group compared with a 2% reduction in the placebo group
  • No new safety signals were identified
  • Cardiometabolic risk factors improved as well, with changes in blood pressure measurements, hemoglobin A1c scores, and cholesterol values.
  • 20%-40% improvements in liver enzymes and noninvasive fibrosis markers, such as ELF and vibration-controlled transient elastography liver stiffness.

My take: This expected finding indicates that more GLP-1 agents are likely to be approved for MASH treatment. Survodutide received “U.S. FDA Breakthrough Therapy” in October 2024.

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Manuel Antonio National Park, Costa Rica

Bariatric Surgery Declines as GLP-1 Medications Rise

USA Today (10/25/24): Bariatric surgeries drop sharply as people turn to Wegovy, Saxenda for weight loss

An excerpt:

The researchers found a 25.6% drop in people undergoing bariatric surgery in the final six months of 2023 compared with the number of surgeries people had during the same period the year before. During the latter half of 2023, the number of patients who took a glucagon-like peptide 1, or GLP-1 medication for weight loss, surged by more than 130%, according to a study published Friday in JAMA Network Open…Another popular weight loss drug, Eli Lilly’s Zepbound, was not included because the Food and Drug Administration did not approve it until November 2023…[And there are] anecdotal reports of hospitals that shut down bariatric surgery programs as the number of patients seeking operations slumped…

In 2022, nearly 280,000 metabolic and bariatric procedures were performed in the United States, according to the American Society for Metabolic and Bariatric Surgery. That represented about 1% of all U.S. residents eligible for weight loss operations…The CDC estimates that about 40% of U.S. residents have obesity and 1 in 10 have severe obesity.

Reference: Lin, K., et al. (2024). Metabolic Bariatric Surgery in the Era of GLP-1 Receptor Agonists for Obesity Management. JAMA Network Opendoi.org/10.1001/jamanetworkopen.2024.41380.

Methods: This cross-sectional study, we used 2022 to 2023 deidentified claims from 17 million unique deidentified adult patients with medical and pharmaceutical coverage through commercial and Medicare Advantage insurance in the OptumLabs Data Warehouse. We included only patients without diabetes and with obesity.

**Only 6% of patients with obesity in the study population received either GLP-1 drugs or surgery, suggesting that many more patients could be receiving treatment.

My take: The GLP-1 drugs have established a medical therapy with a good probability of effectiveness. This was lacking from prior medical treatments. It certainly is logical that their availability could reduce the use of bariatric surgery. The AAP may need to revise their bariatric surgery recommendations from 2020.

Related blog posts:

Bariatric surgery:

GLP-1 Drugs:

Woodley Park-Zoo Metro Station, Washington D.C.

Semaglutide Keeps Weight Off at Four Year Mark

NBC News 5/14/24: Wegovy users keep weight off for 4 years, new analysis finds

“The 17,604-patient trial tested Wegovy not for weight loss but for its heart protective benefits for overweight and obese patients who had preexisting heart disease but not diabetes. Participants were not required to track diet and exercise because it was not an obesity study…”

“Patients in the trial, called Select, lost an average of nearly 10% of their total body weight after 65 weeks on Wegovy. That percentage weight-loss was roughly sustained year-on-year until the end of about four years, where weight loss stood at 10.2%…”

“A third new analysis on Select published by Novo on Tuesday showed that the heart protective benefits of Wegovy to patients in the trial occurred regardless of their weight before starting on the drug and regardless of how much weight they lose on it.”

“The weight loss in the heart trial was less than the average of 15% weight loss in earlier Wegovy obesity studies”

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